Sounds like motor racing is now less dangerous than being a marshal
Ironically, you are right.
That's why we encourage no cellphones while marshalling, never turn your back on a car, newbies to work with seasoned veterans, dead slow in pit and grid areas etc.
And, of course, if it looks like the car coming is too close to get to a cone ... leave the downed cone ... they will get a re-run ... not worth the risk ... so a bit of common sense is to be used also.
Of course, like any sport, there is always an element of risk so we have to manage and minimize it as best as we can since no one wants to run over someone nor get run down. Hence worker stations are chosen carefully (a part of proper course design) etc. And down in the SCCA National events, all the "runners" are required to wear safety vests (we have some too) and people not capable of running (due to disability, age, etc.) are given other jobs such as corner sheet logging and radio or other jobs around the paddock or grid etc. etc.
So, in the end result, the events are still very safe.